The present application is based on and claims priority from Japanese Patent Application 2001-263067, filed Aug. 31, 2001, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a headlamp""s optical axis control system for a vehicle.
2. Description of the Related Art
In a known headlamp""s optical axis control system, the headlamp""s optical axis is controlled to swivel right or left according to the steering angle of a steering wheel. The illumination range of the headlamps is controlled after a driver steers the steering wheel. Therefore, the illumination range of the headlamps may not sufficiently cover an area necessary to observe in front of the vehicle when a vehicle is going to pass a curve.
The present invention has been made in view of the above-stated problem.
It is an object of the invention to provide a vehicle headlamp""s optical axis control system that can swivel the headlamp""s optical axis before a driver steers the steering wheel so that the illumination range of the headlamps can sufficiently cover an area necessary to observe in front of the vehicle when a vehicle is going to pass a curve.
According to a feature of the invention a head lamp""s optical axis control system for a vehicle includes vehicle speed sensor, a steering angle sensor, a navigation system for presenting a road-shape in front of the vehicle, an actuator for swiveling the optical axis of the head lamps, first control means for controlling the actuator to swivel the optical axis according to the vehicle speed signal and the steering angle signal, thereby providing a first illumination range; and second control means for controlling the actuator to swivel the optical axis according to the vehicle speed and the front road-shape presented by the navigation system thereby providing a second illumination range before the steering angle detecting means detects the steering angle if the front road-shape is judged not covered by the first illumination range. Preferably, the second control means provides a turning radius of the vehicle according to the road-shape data. The second control means calculates the turning radius by setting a plurality of points on the curved road through which the vehicle is going to pass. In such a case, the second control means may restore the optical axis to provide the first illumination range if the steering angle is not detected after a preset time passes.